"It's common, and it's been super-empowering to get messages from women all over the world that are like, 'Oh, my gosh. I didn't realize that this was anything, but I got checked, and I have endometriosis,'" she told Redbook.

Hough went to the hospital in 2008 because of stomach pains caused by the disorder. But before being hospitalized, doctors didn't take her pain and health concerns seriously, she told Redbook.

"When I would say I was in serious pain, they'd be like, 'Oh, well, it's probably just your time of the month, and some people have more pain,'" she said. "So when I found out I had a disease, I knew I had to speak out about it. Women deserve to feel heard, accepted, and supported, even if the topic makes some people uncomfortable."

Endometriosis is an "invisible disease" that involves the lining of the uterus and reproductive organs.

According to the Endometriosis Foundation of America, the disorder affects women in "their most productive years" and does not have an identified cause. Endometriosis is typically found in the pelvic cavity, but the foundation reports it can attach to any of the female reproductive organs as well as the bladder and appendix.

Other celebrities have opened up about endometriosis.

Daisy Ridley is another star who suffers from endometriosis. Anthony Harvey/Getty Images

Hough is not the only celebrity who has been vocal about her struggles with endometriosis. Singer Halsey opened up on Twitter about her struggle with the condition in 2016, noting that she was originally miss-diagnosed with PCOS.